boost pin adjust screw

[Tintin]

Here a fun pic to show the pin inside a real pump:




Here now a different lengh of the feeler pin (guide pin),  the longest allow more fueling on-boost with proper boost pin or proper boost pin grinding.

[hillfolk'r]

the plastic washer acts like a cushion when the pin is driven downwards , i wouldn't recomend removing it .

as you can see my pin isn't being pushed all the way down any way by boost presure , so the next best thing is to grind deeper into the pin where the small pin rides on the fuel pin , allowing more fuel in the range that the small  pin rides on the fuel pin .


 and yes  after your done grinding , it has to be polished smooth .

mines been with no (plastic)washer for years...my pump guy told me its ok to remove it for better pin travel,etc
its not like its hammering itself on the top of the pump casting or somethin

[Benjamin]

Here a fun pic to show the pin inside a real pump:




Here now a different lengh of the feeler pin (guide pin),  the longest allow more fueling on-boost with proper boost pin or proper boost pin grinding.

nice, i was also thinking to build something like that, to adjust the pressure very good, becouse otherwise you cant know when the lda is down at what boost.

this is very very intrested information tintin!
So if you put a longer feeler pin, can the other parts in the VE also support more advance?



Greetz, Benjamin

[k77aus]

Does anyone have any links / info on tuning my stock uk 1.6GTD Mk2 golf - Here is the spec
SB code engine 80bhp
Intercooler mounted in engine bay on slant
290,000 miles
45-48mpg
0.7 Bar boost pressure

I'm after reliable power increase that can be used every day and still return a decent miles per gallon. ANY ADVICE OR LINKS would be appreciated

[boxer246]

K77aus......here's the best info:

http://vwdiesel.net/phpBB/viewtopic.php?t=645

[KTZed]

I just got around to turning the boost pin to the steepest ramp in my 1.6TD and I'm glad to say it made quite a big difference. More power overall but more importantly, the turbo spools sooner and faster giving me a usable midrange. I also cut the plastic washer in half to allow more travel and I cant say I noticed a difference. It still doesnt smoke much and the EGT's are under control so theres room for more and I'd still like to get better spool/midrange power. My next mods will be turning the max fuel screw in to up the fuel over the entire range, turning the starwheel down to allow more fuel sooner in relation to boost, and turning the smoke screw up to allow the starting point to be close to stock for better economy.

[burnt_servo]

right now , with my car , at 18 pounds of boost , and the softest vw boost diaphram spring i could find locally ( it's blue / greenish ) , and the star wheel all the way down ,  i'm not bottoming the pin in side the housing yet .....

so i suspect  cutting the washer in 1/2 won't be of benifit until much higher boost pressures are reached ( meaning a metal headgasket and arp studs ) .

grinding the fuel pin will achieve  more fuel at any given boost level , and spooling the turbo up much  much faster  than the steepest stock setting .

[KTZed]

grinding the fuel pin will achieve more fuel at any given boost level

As far as I understand, thats what the max fuel screw adjusts. I would rather play with that than grind my pin because its easier and fully reversible.
You may be right about the washer though...I will do some testing and calcs to figure out the spring constant so I can graph the boost pressure vs fuel pin position.

[Baxter]

RE: removing the washer.

Would it not be a good idea to replace the thick plastic washer with a small rubber o-ring, that way you still have some cushioning and increased travel.
just a thought.

[burnt_servo]

something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine )  , there isn't enough presure  even with the softest vw diaphram spring to bottom out the fuel pin .

so cutting , removing  or replacing the plastic washer does nothing till you reach the higher boost levels .

[jimfoo]

something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine )  , there isn't enough presure  even with the softest vw diaphram spring to bottom out the fuel pin .

Just wondering how you are figuring that?

[burnt_servo]

something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine )  , there isn't enough presure  even with the softest vw diaphram spring to bottom out the fuel pin .

Just wondering how you are figuring that?

just watching the marks in the grease on the pin , and figuring out how far it travels downward .  with a greenish blue spring ( the lightest vw  spring i've found so far ) the 20 psi  peak my turbo hits isn't bottoming the pin .

to counter the pin not bottoming , i ground a deeper  taper into the pin

[zukgod1]

RE: removing the washer.

Would it not be a good idea to replace the thick plastic washer with a small rubber o-ring, that way you still have some cushioning and increased travel.
just a thought.

Now I'm not bashing you with this comment Mr Brick I just need to do say something.

I've read more than once here that people (may only 2) are concerned about removing the plastic washer..

Lets look at that for a sec shale we?
First off there is never enough force in there to do any harm with the washer removed. I do not believe it's purpose is cushioning. If anything its there to limit travel.

The plastic washer moves the pin farther down at the no boost setting due to the thickness.
If it's removed the pin sits higher at no boost thus a tad less fuel till boost builds. If you leave it there you have that very little bit of more fuel off idle.

What I did was to remove it and install a metal washer in it's place that was the same DIA as the pin so it would have more travel, maybe only 2mm at the most but we are talking about mm of adjustment here anyway.
I custom ground the pin to have a more aggressive slope and I removed some material from the bottom as well as the pin was hitting the bottom of its travel and not using the full ramp.
this gave me more usable fuel on the top end.
I hit 30psi all the time so pressure isn't a issue with me as to spring pre load. I have the pre load on the spring turned way up to the top so it's really still so it smokes less at low rpms. Once I'm rolling and the boost hits past 5 psi I can fell the fuel increase allot more.
Goes from 5psi to 25 FAST.

I'm thinking of grinding another pin with a mild slope the first 1/4 of it maybe then a aggressive slope after that so my usual around town driving is less smoky until I mash it and once it hits the steep part of the slope it will dump more fuel in..